1. Field of the Invention
The present invention relates to a headrest support rod including a bent steel rod which is overmolded with plastic sleeves to minimize weight and reduce manufacturing costs.
2. Background Art
In a vehicle seat assembly, a headrest is typically supported on top of a seat back by a steel headrest support rod. The steel rod is typically a 1018 steel which is bent to a desired shape and then broached to form adjustment slots along the sides of the rod. The ends of the rod are turned to eliminate any sharp edges, and the rod is then chrome-plated to provide an attractive appearance.
The above-described broaching, chrome-plating and turning processes add significant expense to the manufacture of the headrest support rod. Accordingly, it is desirable to reduce costs associated with manufacturing of the headrest support rod.
The present invention provides an improved headrest support rod and method of manufacturing the same in which a cylindrical steel rod of reduced diameter is bent to a desired shape and plastic sleeves are injection molded over first and second legs of the bent rod. By using plastic sleeves, the broaching, turning and chrome-plating processes are eliminated while reducing weight of the headrest support rod.
More specifically, the present invention provides a method of manufacturing a headrest support rod including the steps of: a) bending a cylindrical steel rod into a desired shape including first and second legs; b) placing the bent steel rod into an injection mold; and c) injection molding first and second plastic sleeves over the first and second legs, respectively, to complete the headrest support rod, thereby minimizing weight of the headrest support rod.
Preferably, the first and second plastic sleeves include lock slots molded therein to facilitate locking or position adjustment of the headrest support rod with respect to a guide bushing on the seat back.
Also, preferably, the steel rod is between approximately 6 mm and 10 mm in diameter, and most preferably approximately 8 mm in diameter. The plastic sleeves are preferably substantially cylindrical and hollow in shape with 2 mm thick walls so that the completed headrest support rod is approximately 12 mm thick in diameter along the first and second legs when the steel rod is 8 mm in diameter.
Preferably, the cylindrical steel rod is an SAE 1045 steel, and the plastic sleeves are a nylon material which shrinks after injection molding onto the rod to facilitate a secure attachment of the plastic sleeves to the steel rod.
Another aspect of the invention provides a headrest support rod apparatus including a bent steel rod having first and second legs with first and second plastic sleeves injection molded over the first and second legs, respectively, to complete the headrest support rod, thereby minimizing weight of the headrest support rod. Preferably, the first and second plastic sleeves include lock slots formed therein.
Accordingly, an object of the invention is to provide an improved headrest support rod and an improved method of manufacturing a headrest support rod in which manufacturing costs are reduced.
Another object of the invention is to provide an improved headrest support rod in which broaching, turning and chrome-plating processes are not necessary.
A further object of the invention is to provide a headrest support rod in which a steel rod is bent into a desired shape including first and second legs, and plastic sleeves are injection molded over the first and second legs to complete the headrest support rod.
A still further object of the invention is to provide a headrest support rod including a bent steel rod with plastic sleeves molded thereon wherein lock slots are formed in the plastic sleeves in the injection molding process to eliminate the broaching process from the manufacture of the headrest support rod.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.